Conformity assessments create producer and consumer confidence in the marketplace, as products under statements of conformance meet certain design and safety requirements from specific standards.
What Are Statements of Conformity?
Statements of conformity are defined tolerance limits in these assessments to determine if the property is either conforming or non-conforming. The limits established in the conformity assessment process determine the balance of risks that affect the consumer’s and producer’s risk.
Defining and Outlining Statements of Conformity in ISO/IEC 17025
ISO/IEC 17025:2017 provides an outline for statements of conformity. Before conducting the activities to determine if a property is conforming or non-conforming, the laboratory must have a procedure to review the contract. The procedure will ensure that:
- The requirements are adequately defined, documented, and understood
- The laboratory has the capability and resources to meet the requirements
- Where external providers are used, the requirements of 6.6 are applied and the laboratory advises the customer of the specific laboratory activities to be performed by the external provider and gains the customer’s approval
- The appropriate method or procedures are selected and are capable of meeting the customers’ requirements
The customer can request a statement of conformity to a specification for the test, in which the decision rule must be clearly defined. The decision rule describes how measurement uncertainty is accounted for when stating conformity. The laboratory is responsible for informing the customer if a method requested is inappropriate for the statement of conformance. There is clear communication throughout the process—if there are any further changes made in the laboratory activities, they will be conveyed to the customer, and the contract will be amended to reflect those changes.
Examples of Statements of Conformity Decision Rules
As further explained in ISO/IEC Guide 98-4:2012, a widely used decision rule is known as “simple acceptance” or “shared risk.” This means that the producer and consumer of the measurement result agree to accept or reject an item as conforming to the tolerance interval. The acceptance of the decision rule for the producer and consumer gives them shared consequences of incorrect decisions. To keep incorrect decision levels acceptable, it is required that the measurement uncertainty be acceptable for the intended purpose.
Another decision rule that can be followed is the “accuracy method,” in which sources are minimized by the measuring instruments used, environmental factors, and well-documented control of laboratory procedures and measurement personnel. More about this rule can be found in IEC Guide 115.
Reporting Statements of Conformity
When the statement of conformity is provided, the laboratory will document the decision rule employed and apply it, considering the levels of risk. The laboratory will report on the statement of conformity so that it identifies:
- To which results the statement of conformity applies
- Which specifications, standards, or parts thereof are met or not met
- The decision rule applied (unless it is inherent in the requested specification or standard)
If there are other interpretations expressed, the laboratory will make sure that authorized personnel release a respective statement. If any changes are needed, the change of information will be identified and included in the report.
Reporting statements of conformity benefits both the producer and consumer, as it provides greater trust in the properties produced. To learn more about this topic, please watch this ANAB webinar on ISO/IEC 17025:2017 and Statements of Conformity.